Effect of organo clay content on proton conductivity and methanol transport through crosslinked PVA hybrid membrane for direct methanol fuel cell

In the present study, crosslinked poly(vinyl alcohol) (PVA) membranes were prepared using poly(styrene sulfonic acid-co-maleic acid) (PSSA_MA) (PVA:PSSA_MA = 1:7). The PSSA_MA was used both as a crosslinking agent and as a donor of the hydrophilic group (–SO₃H and/or –COOH). The hybrid membranes were prepared by modified clay such as Clay Na⁺, Clay 30B, and Clay 15A. The thermal, water uptake, proton and methanol transport properties of the hybrid membrane were found to be sensitive to the clay type and content. The hybrid membrane with Clay 30B shows higher proton conductivity than other hybrid membranes due to hydroxyethyl group. The membrane with Clay 15A showed the lowest methanol permeability due to lower specific gravity than other clay. Compared to the membrane without modified, the PVA/PSSA_MA/Clay 15A containing 4 wt% of Clay 15A showed both high proton conductivity (0.023 S/cm) and low methanol permeability (2.19 × 10^?7 cm²/s).     

Electric‐Field‐Controlled Dopant Distribution in Organic Semiconductors

Stable electrical doping of organic semiconductors is fundamental for the functionality of high performance devices. It is known that dopants can be subjected to strong diffusion in certain organic semiconductors. This work studies the impact of operating conditions on thin films of the polymer poly(3‐hexylthiophene) (P3HT) and the small molecule Spiro‐MeOTAD, doped with two differently sized p‐type dopants. The negatively charged dopants can drift upon application of an electric field in thin films of doped P3HT over surprisingly large distances. This drift is not observed in the small molecule Spiro‐MeOTAD. Upon the dopants’ directional movement in P3HT, a dedoped region forms at the negatively biased electrode, increasing the overall resistance of the thin film. In addition to electrical measurements, optical microscopy, spatially resolved infrared spectroscopy, and scanning Kelvin probe microscopy are used to investigate the drift of dopants. Dopant mobilities of 10^?9 to 10^?8 cm² V^?1 s^?1 are estimated. This drift over several micrometers is reversible and can be controlled. Furthermore, this study presents a novel memory device to illustrate the applicability of this effect. The results emphasize the importance of dynamic processes under operating conditions that must be considered even for single doped layers.     

Generation of Discrete Bicubic G^1 B-Spline Ship Hullform Surfaces from a Given Curve Network Using Virtual Iso-Parametric Curves

We propose a method that automatically generates discrete bicubic G^1 continuous B-spline surfaces that interpolate the curve network of a ship huliform.First,the curves in the network are classified into two types;boundary curves and ＂reference curves＂,The boundary curves correspond to a set of rectangular（or triangular）topological type that can be representes with tensot-product （or degenerate）B-spline surface patches.Next,in the interior of the patches,surface fitting points and cross boundary derivatives are estimated from the reference curves by constructing ＂virtual＂isoparametric curves.Finally,a discrete G^1 continuous B-spline surface is gencrated by a surface fitting algorithm.Several smooth ship hullform surfaces generated from curve networks corresponding to actual ship hullforms demonstrate the quality of the method.     

Effect of surface modifying macromolecules on the properties of poly(vinylidene fluoride) membranes

Poly(vinylidene fluoride) (PVDF) membranes were surface-modified using fluorotelemer intermediate Zonyl BA-L as a fluorinated surface modifying macromolecules (SMM) additives in the concentration range from 0 to 2 wt.%. Prepared membranes were characterized by contact angle measurement, electron spectroscopy for chemical analysis (ESCA), scanning electron microscopy (SEM), and pervaporation test. The experimental results showed that SMM migrated to the surface and effectively increased the surface hydrophobicity of the PVDF membranes. The pure water permeation flux evaluated by pervaporation decreased with an increase in the content of SMM.     

Preparation of polypropylene/poly (butylene adipate-co-terephthalate) composite films incorporated with melanin for prevention of greening of potatoes

Polypropylene (PP) and poly (butylene adipate-co-terephthalate) (PBAT) blend films incorporated with melanin (Mel) were prepared using an extrusion casting method. Scanning electron microscopy results showed that Mel was evenly dispersed to form a well-blended film. The PP/PBAT/Mel composite films prevented UV light transmittance, especially UV-B rays. The addition of Mel influenced the surface color, water vapor transmission rate, oxygen transmission rate, and water contact angle of the composite films. After the addition of Mel, the tensile strength and elongation at break in the machine direction of the composite film increased by 30% and 27%, respectively. Packaging potatoes with PP/PBAT/Mel film and storing them under fluorescent light for 6 days effectively prevented the greening of potatoes caused by the production of chlorophyll. The PP/PBAT/Mel films have a high potential for the prevention of greening of potatoes during storage and distribution.     

Monitoring of Intracellular Tau Aggregation Regulated by OGA/OGT Inhibitors

Abnormal phosphorylation of tau has been considered as a key pathogenic mechanism inducing tau aggregation in multiple neurodegenerative disorders, collectively called tauopathies. Recent evidence showed that tau phosphorylation sites are protected with O-linked β-N-acetylglucosamine (O-GlcNAc) in normal brain. In pathological condition, tau is de-glycosylated and becomes a substrate for kinases. Despite the importance of O-GlcNAcylation in tau pathology, O-GlcNAc transferase (OGT), and an enzyme catalyzing O-GlcNAc to tau, has not been carefully investigated in the context of tau aggregation. Here, we investigated intracellular tau aggregation regulated by BZX2, an inhibitor of OGT. Upon the inhibition of OGT, tau phosphorylation increased 2.0-fold at Ser199 and 1.5-fold at Ser396, resulting in increased tau aggregation. Moreover, the BZX2 induced tau aggregation was efficiently reduced by the treatment of Thiamet G, an inhibitor of O-GlcNAcase (OGA). Our results demonstrated the protective role of OGT in tau aggregation and also suggest the counter-regulatory mechanism of OGA and OGT in tau pathology.     

Radionuclide therapy of skin cancers and Bowen's disease using a specially designed skin patch

Skin cancer is the most common malignancy in humans. Therapeutic modalities for skin cancer are local destruction, radiotherapy and surgery. External radiation therapy leads to good results, however, generally 5-6 wk of treatment is needed to deliver optimal radiation dose to tumors. In this study, a beta-emitting radionuclide, 166Ho, impregnated in a specially designed patch, was used on superficial skin cancers and Bowen's disease for local irradiation. METHODS: Ten mice with chemically induced skin tumors were studied. Five-millimeter size patches containing 22.2-72.15 MBq (0.6-1.95 mCi) 166Ho were applied to the tumor surface for 1-2 hr. In a human trial, patients with squamous-cell carcinoma (n = 3), basal cell carcinoma (n = 1) and Bowen's disease (n = 1) were treated with patches containing 273.8-999 MBq (7.4-27 mCi) of 166Ho for 30 min to 1 hr. Pathologic examination was performed 4-7 wk after treatment in an animal model. Skin biopsy was performed 8 wk post-treatment in four patients. RESULTS: Tumor destruction was seen 1 wk post-treatment, however, radiation dermatitis or ulceration developed at the site of radionuclide application. Those reactions healed gradually with fibrosis or epithelialization, which was confirmed pathologically. No significant adverse reaction to radiation except subcutaneous fibrosis was found. CONCLUSION: Superficial skin tumors could be successfully treated by topical application of beta-emitting radionuclides.     

A human vascular endothelial cell model to study angiogenesis and tumorigenesis

Proliferation, differentiation and regulated trafficking of cells are the hallmarks of development and embryogenesis. This led us to speculate a role for chemokines and their receptors in this process. Here, we report the molecular cloning of AvCRL1, a novel member of the G-protein coupled receptor family from early stage 3 days old chick embryos. While the function and ligand for this receptor remain unknown, its sequence and gene structure indicates that it is most related to the family of chemokine receptors, with highest homology to the virally induced human BLR-1 and the CXCR3 or gammaIP-10/Mig-1 receptors.     

Aerodynamically induced power loss in hard disk drives

In this paper, the effects of rotational speed, form factor and enclosure conditions on power dissipation in hard disk drives are presented. The aerodynamically dissipated power losses by 3.5, 2.5 and 1 in. hard disks are experimentally measured using a vacuum chamber and compared to theoretical estimations. Experiments in open air without enclosure agree well with theoretical predictions; a 3.5-in. disk satisfies the turbulent model but 1 and 2.5-in. disks match the laminar one, which is inversely proportional to the half power of Reynolds number. Experiments using a single 3.5-in. disk in enclosure show that aerodynamic power loss is proportional to the second power of rotational speed and the fourth power of disk radius, which agrees with the laminar theory rather than turbulent one. It is also shown that the aerodynamic power loss is reduced as the axial gap and radial clearance of enclosure decrease.     

Moisture Loss and Lipid Oxidation for Precooked Beef Patties Stored in Edible Coatings and Films

Edible/biodegradable wheat gluten (WG), soy protein (SP), carrageenan (CA) and chitosan (CH) films and coatings were used on precooked beef patties. After 3 d of refrigerated storage, no difference was found in moisture loss between WG, SP, and CH film-wrapped patties and unpackaged patties (control-A). All coatings were as effective as polyvinyl chloride film (control-B) in reducing moisture loss. CA film decreased moisture loss but not as effective as control-B. WG, SP, and CA coatings and CA film reduced thiobarbituric acid-reactive substances and hexanal values compared to control-A. WG-coated patties had lower hexanal values than control-B samples. WG, SP, and CH films were not effective in controlling lipid oxidation.